1. Field of the Invention
The invention relates to fittings for connecting columns and beams of a steel frame construction and a method of connecting columns and beams and more particularly suitable for connecting beams having an H-shaped section to a web of a column having an H-shaped section.
2. Description of the Prior Art
In prior art steel frame construction, T-shaped members each of which may be obtained by cutting H-shaped steel have often been used for connecting columns and beams. However, such T-shaped members are insufficient to transmit a shearing force acting on the beam to the column, so that a web of the beam must generally be connected to a flange of the column by means of separate joint members which would make the construction method complicated and expensive.
In another prior art steel frame construction, welding members of steel plate are welded to the flanges of the beam for connecting the column to the beam. In that case, however, the beam must be provided at corners between its flanges and web with notches required for welding operation. Accordingly, the notches make it insufficient to transmit a shearing force acting upon the beam to the column so that separate joint members are also required for the construction. Moreover after the plate members have been connected to the web of the beam by means of a fillet weld joint, the plate members may be deformed owing to stresses caused in welding which must be corrected by a troublesome method. If concentrated stresses acting upon the column from the flanges of the beam are relatively large, horizontal reinforcement plates must be welded between the flanges of the column for the purpose of a reinforcement of the construction.
In further prior art steel frame construction, columns and beams are directly connected by welding. In the connecting method, if heights of the beams gathered together at the column are not equal, horizontal reinforcement plates are required as in the prior art above described. It is usual to weld short length beams to the column in order to make it easy to transport the column from a factory to a field, but the transportation of the column having welded the short length beams is more difficult than that of single columns or beams, and such a column requires a troublesome operation for connecting the short length beams to more longer or standard beams with splice plates in the field. Moreover, there would be required bevelings at edges of the beams to be welded and notches at corners between the flanges and the webs of the beams which require a complicated working, and the webs of the beams are in intimate contact with the column for fillet welding, so that the edges of the beams to be welded should be worked with a sufficient high accuracy.
As described above, in the prior art, connections of columns and beams in steel frame construction generally required extra joint members and need complicated working and assemblies of the members and further have only low joint efficiency.